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Old July 25th, 2018, 18:47   #1
Join Date: Jul 2018
Location: Dayton, ohio
Default Ac help

Hello everyone,

I recently purchased my first tdi, it's a 1998 jetta 5 speed. I purchased it off of a friend of mine and I've been loving it so far besides one thing, the ac just quit working. I've messed with a few ac systems before and I do know the basics, there are just a few things that I haven't seen before that are on this car. Well since I've been driving it the ac has been progressively getting warmer and warmer air as the days went on and then it suddenly stopped working a few days ago. I was told it leaked freon slowly and that I would just have to charge it up everyone once and a while, now I'm not that kind of guy i would rather fix it and be done. I went to recharge it and at least see that the pressure was at on the low side, I have access to manifold gauges and vacuum pump just haven't gotten them yet, but my basic bottle guage would clip on to the low side but it wouldn't display any pressure or allow me to pump any freon Into the system. So I unhooked it and looked at the scrahder valve and I have never seen one like this before, typically they just look like a Schrader valve like what's in a tire, but this one was like a rubber ball that's sitting where the Schrader valve is at. I pulled the call off of the high pressure side to see if it had the same thing and it did. I also noticed a fair amount of ac dye on with the high and low side service valves, I'm assuming that's where my leak is at. So I stopped there after not finding any information on the internet to explain the rubber ball or a picture of one either. I went to the parts store to see if they had a new set of hoses I could look at and see if it had the same ball in the valve, turns out they don't even offer them. I borrowed one of their bottle guage and I was able to see the pressure on the low side, it was hanging out around 25 psi once the compressor kicked on, did not get low enough for it to shut back off though. I wasnt able to get the compressor to turn on before that though so I thought it was odd. Anyways I tried to add some freon to the system and it almost wouldn't take any. I'm talking like maybe 27 psi or so. I shut the ac off and let it sit for a second and went to turn it back on and the compressor barely moved, it was acting like it hit a hard spot or something but kept doing it over and over again. It would turn like 20°to 30° and stop then repeat over and over again. I turned it off and gave up after that. I didn't want to hurt it. Then just today I was sitting in a drive thru and waiting too long so I tried to turn the ac on to see if it would work and it did for about 5 minutes then it shut off again.

Basically what I'm wanting to know is if all the cars have the same rubber ball type valve instead of a Schrader valve and is it replaceable? I can get the new fitting with the Schrader valve in them form the parts store but I don't want to try to remove them from aluminum hoses that I can't find replacements for if I damage them. I was planning on evacuating the system and pulling a vacuum on it and adding new freon, mainly because I suspect that there is a lot of stop leak in there. Also want to replace the valves since that's where I'm thinking its leaking from.

Anyways all help will be really appreciated and I will get a picture of those valves as soon as I get off of work so you can see what I mean.

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Old July 25th, 2018, 19:39   #2
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Join Date: May 2003
Location: Southeast Kentucky

The dye is there probably because the previous owners were introducing it to determine where the refrigerant leak might be.

The round ball looking thing is the check valve which is pretty much fool proof. It is designed for the new and improved style manifold gauges. They are much easier to use.

R134a Refrigerant goes in slow. If you have access to a set of manifold gauges, use them to understand more about what's going on with your AC system.

I'm not sure about the 98 era Jetta's, but the later models have had issues with insulation on the louver doors inside the fan housing flaking off. This allows the heater hot air to mix with the colder AC air....

Lastly, the AC compressor not turning over smoothly is highly suspect. It should either rotate freely or not at all.
'84 Vanagon '02 ALH TDI engine Malone Stage 1 tune. CAT, SS 2" exhaust, E-vac system, DMF with upgrade pilot shaft, 4.57 R&P, fan assisted IC. (32 to 35+ MPGs consistently)
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